Rapid green synthesis of palladium nanoparticles using grape seed extract for catalytic reduction of 4-nitrophenol and crystal violet

Palladium nanoparticles (PdNPs) preparation using waste grape seed extract (GSE) as reducing and stabilizing agent was studied via microwave-assisted method. Variation of reaction conditions such as solution pH, concentration of PdCl2, and concentration of GSE was studied in detail. Good formation of PdNPs was observed in acidic conditions and formation decreased with increase in pH. Alkaline conditions were found not suitable for PdNPs formation using GSE. As obtained GSE capped PdNPs (GSE@PdNPs) were well characterized using various analytical techniques. TEM analysis revealed the well separated particles with spherical morphology. The particle diameters were observed in the scale of 4 to 13 nm with a mean diameter of 8±2 nm. The crystal structure was determined to be face centred cubic (FCC) using XRD and SAED patterns. FTIR analysis exposed the role of phytochemicals present in GSE in the reduction and stabilization of PdNPs. Zeta potential analysis revealed the negative surface charge (– 24 ± 1.21 mV) on GSE@PdNPs and good colloidal stability. Catalytic ability of GSE@PdNPs was assessed by the NaBH4 assisted reduction of 4-nitrophenol (4-NP) and crystal violet (CV). Reduction reactions followed the pseudo-first order kinetics with rate constant values of 0.090±0.015 min−1 for 4-NP and 0.252±0.036 min−1 for CV.